Radio viewing system



April 15, 1947- H. A. lAMs 2,419,024

RADIO VIEWING SYSTEM Filed Feb. 21, 1945 2 Sheets-Sheet 1 1 EHMRUF/EBL EEO/F057?- April 15, 1947. W 2,419,024

RADIO VIEWING SYSTEM Filed Feb. 21, 1945 2 Sheets-Sheet 2 mast v i 14 4'; i/ 4 r ZE/V5/55747/0A/fl/7) I7 VEN TOR.

lfwlsgfllams Patented Apr. 15, 1947 RADIO VIEWING SYSTEM Harley A. Iams, Princeton, N. 3., assignor to Radio Corporation of America, a corporation of Delaware Application February 21, 1945, Serial No. 579,076

6 Claims.

. 1 My invention relates to systems for viewing scenes in darkness or obscured by fog, smoke or the like, and in particular it relates to systems of this type wherein the scene is recorded.

An object of the invention invention is to provide an improved method of and means for obtaining a View of a scene by utilizing radio waves reflected therefrom.

A further object of the invention is to provide an improved method of and means for recording a scene that is obscured by darkness, fog or the like.

In practicing the invention, the radio waves from a scene are imaged by means of a. mirror or a lens and this image is scanned by means of a pick-up device such as a detector or the end of a wave guide which i arranged to conduct the radiation to a detector. The signal from the pick-up device is amplified and supplied to a facsimile recorder or the like which is driven in synchronism with the scanning of the radio wave image whereby a record of the scene is obtained.

The invention will be better understood from the following description taken in connection with the accompanying drawing in which Figure 1 is a View in perspective of one embodiment of the invention,

Figure 2 is a side view of the apparatus shown in Fig. 1,

Figure 3 is a view in perspective of a wave guide scanning arm that may be substituted for the scanning arm shown in Figs. 1 and 2, I

Figures 3a and 3b are cross-sectional and end views, respectively, of a rotatable wave guide joint shown in Fig. 3,

Figure 4 is a plan view of a second embodiment of the invention, Figure 5 is a side in Fig. 4, I Figure 6 is a perspective view of a third embodiment of the invention, and

Figure 7 is a view that is referred to in discussing the operation of the invention illustrated in Fig, 6.

In the several figures, similar parts are indicated by similar reference characters.

Referring to Figs. 1 and. 2, the radio waves from a scene to be viewed are imaged by a concave mirror I i! such as a spherical mirrorsupported by a shaft 9, the image being formed in the plane of a swinging pick-up device I I. The waves from the scene are obtained by illuminating or flooding the scene with radio waves of a wave length view of the apparatus shown short enough to permit the formation of a sufii- F ciently sharp image with an optical system of convenient size, but long enough to pass through clouds and fog. Wave lengths of about one centimeter, for example, or shorter, are suitable.

The pick-up device II is mounted on a scanning arm I2 that is pivotally supported at I3 on the base of a facsimile recorder M. The recorder M, in the example shown, is of the well known type comprising a rotatable drum I6 that has a sheet of current-sensitive paper wrapped around it. The drum I6 is rotated through suitable gearing by a motor I'l.

The recording stylus I8 is supported on a carriage block I9 that is supported in screw-threaded relation on a threaded rod 2I whereby the stylus I8 is moved longitudinally along the drum IE when the rod 2| is rotated. The rod 2| is rotated through gears 22 by the motor I! thus moving the stylus is along the drum I6 as the drum is rotated.

At the same time, the pick-up device I I is swung in the plane of the image from left to right and return during each complete rotation of the drum It by means of a crank arm 23 that engages a slot 26 in the scanning arm I2. Also, as the stylus i8 moves along the drum I6, a link member 26 that connects the stylus carriage block I9 to an arm 21 of the mirror shaft 9 causes the mirror It] to tilt, thereby moving the image in the vertical direction with respect to the pick-up device II. It will be apparent that as a result the complete image is scanned by the device II,

the scanning being rapid in the left-right or horizontal direction and slow in the up-down or vertical direction.

The pick-up device I I may be a crystal detector or the like as assumed in the example of Figs. 1 and 2, or it may be the end II of a wave guide I2 as illustrated in Fig. 3. The wave guide I2 is mounted on the facsimile recorder I4 in the same way the scanning arm I2 is mounted thereon with the pin of the crank arm 23 engaging a slot 2d. At the pivot point I3, the wave guide I2 is provided with a rotatablejoint [2a whereby the energy picked up at II may-be supplied through a wave guide section I 2b to a suitable detector (or mixer) and amplifier not shown. As in the case of the embodiment of Figs. 1 and 2, the detected and amplified energy from the pickup device is supplied to the stylus I8 where a mark is made on the recording paper due to the current flow from the stylus. As is well understood inthe art, the' mark is dark or light depending upon the amplitude or density of the current supplied to the stylus whereby a picture correspondin to the image is obtained. With the scanning arrangement illustrated in Figs. 1 and 2, two pictures will be obtained on the paper surrounding the drum it, one that is produced when the scanning arm l2 swings to the left and one that is produced when the scanning arm it? returns to the right.

By employingthe wave guide and concave mirror combination at the transmitter, the scene may be illuminated by flyin snot scanning. This transmitter arrangement is the reverse of the receiver combination of spherical mirror it of Fig. 1 and wave guide of Fig. 3 in that the energy from the transmitter is radiated from the wave guide opening ii toward the mirror iii. In the case of flying spot scanning the transmitter and receiver scanning must be synchronized as is Well understood in the art.

If the transmitter is pulsed, well known radar technique may be employed for utilizing a common wave guide and mirror combination for both transmitting and receiving. In a'pulsed system there should be at least one pulse transmitted for each desired picture element. Following radar practice, the receiver may be gated so that only echo pulses received during a certain time in terval following trasmission of a pulse are applied to the facsimile recorder. Thus, a picture may be obtained showing only objects within a certain distance from the transmitter.

Figs. 4. and 5 show an embodiment of the invention wherein the radio waves reflected from a scene are imaged by a suitable lens M which may be made of a low-loss dielectric such as paraffin, for example, and which may be two or three feet in diameter.

Th motor ll'and the recorder M are mounted on a platform 32 that has one end pivotally supported at 33 under the center of the lens 38. The other end of the platform 32 is supported on a pair of wheels 34 and 36. The wheel 35 is driven by the motor ll through a belt 31 and pulleys 38 and 39 so that the platform 32 is swung about the pivot point 33 as the recorder is operated.

The lens 3! remains stationary. Thus the pick-up end it of a wave guide M is moved horizontally at a slow rate across the image formed by the lens '3 l.

The end it of the wave guide "ii scans the image in the vertical direction at a comparatively rapid rate, the motion being from bottom to top and return for each rotation of the drum it. This rapid vertical scanning is obtained by pivotally mounting one end of the wave guide ii on a pair of supporting members 52 and t3, the said one end being opposite he horn of a wave guide Ma leading to a detector (not shown). Instead of the pivotal mounting illustrated, a rotatable wave guideioint may be employed. A member M attached to the wave guide ii has a slot therein corresponding to the slot 2 shown in Fig. 3. The slot in-rnember M is engaged by a crankarm pin it that is driven by the shaft of the drum to whereby the wave guide it oscillates up and down as the drum rotates. With this arrangement the complete image is scanned Without tilting thelens 3!. It will be understood that the lens 3! may be replaced by a concave mirror if desired.

From the pivoted end of the wave guide d! the energy picked up from the radio wave image is supplied through additional wave guide structure (not 'shown) to a suitable detector and amplifier (not shown). As in the system shown in Figs. 1

and 2, the amplified signal is then supplied to the recorder stylus E8.

Fig. 6 illustrates an embodiment of the invention where the motion of an airplane is used to 5 provide the scanning motion in one direction, this scanning motion corresponding to the tilting of the mirror in Fig. 1.

As shown in Fig. 6, a lens 5| is mounted in the bottom of the plane to form an image of the terrain below. The image of an object on the ground sweeps across the path of a swinging Wave guide at a comparatively slow rate as the plane advances. The wave guide 52 is oscillated about a pivot point 5'! of a rotatable wave guide joint 530; at a comparatively rapid rate by means of a crank pin (not shown) that engages a slot A stylus t t is supported on an arm 59 that, in turn, is pivotally attached at its ends to the wave guide and to a supporting arm 6|. The

'52 is supported at a pivot point 62. Synchronized wi the speed of the plane, a sheet of out tive facsimile paper 53 is passed the stylus 555 which is oscillated by the wave The paper 53 is marked by the current stylus to paper as in usual facsimile recorders, thus producing a strip map of the route which has been covered. This map can be used to follow a river or railroad to the target. By scanning a line 56 on the earths surface that is a certain distance ahead of the airplane, as indicated in Fig. '7, time can be allowed for the release of the bomb after the target has been identified.

The rotatable-wave guide joints referred to in connection with the preceding figures may be of the type shown in Figs. 3a and 31), if desired. Several dimensions are given in inches in the two figures by way of example for the case where the wave l- I the radio Wave is substantially Figs. 3a and 3b are largely selfit may be noted that the ends of the wave guides i2 and 52b contain plugs 86 and ti, respectively, whichprovide steps opposite 1e circular wave guid elements 520 and l2a, re spectively, of the rotatable joint. These step portions cause th radio wave from a rectangular wave guide to travel into and through the circular wave guide portions lZa and We and then to the other rectangular wave guide with but tie loss energy. Th circular slot 68 and the ociated end spacing 63 act as a choke or filter keep the radio waves from leaking out of the joint.

I cla; n. as my invention: 7

1. In ombination, means for imaging radio Waves from a scene to be recorded, a radio Wave pick-up device comprising a crystal detector, means for scanning the said radio Wave. image by pick-up device and converting the energy thu picked up into an electrical signal, a facl corder, means for operating said recorder onism with said scanning, and means for su plying said signal to said recorder Whereby a picture of said scene is recorded.

2. In combination, means for imaging radio waves from a scene to be recorded, a radio wave pick' up device comprising a wave guide; means for scanning the said radio wave image by said pick-up device and converting the energythus picked up into an electrical signal, a facsimile recorder, means for operating said recorder in syn hronism with said scanning, and means for supplying said signal to said recorder whereby a picture of said scene is recorded.

3. In combination, means for imaging radio explanatory but waves from a scene to be recorded, a radio wave pick-up device, means for scanning the said radio wave image by said pick-up device and converting the energy thus picked up into an electrical signal, said means for scanning said image comprising means for moving said pick-up device comparatively rapidly across said image in one direction, and means for tilting said image comparatively slowly substantially at right angles to said one direction, a facsimile recorder, means for operating said recorder in synchronism with said scanning, and means for supplying said signal to said recorder whereby a picture of said scene is recorded.

4:. A scanning device comprising a mirror for focusing radio waves, means for tilting said miror about an axis to scan in one direction, a pick-up device for receiving said radio waves, and means for moving said pick-up device substantially parallel with the axis of tilt of said mirror.

5. In combination, means for imaging radio waves from a scene to be recorded, a radio wave pick-up device comprising a crystal detector, means for scanning the said radio wave image by said pick-up device and converting the energy thus picked up into an electrical signal, an image reproducing means, means for operating said image reproducing means n synchronism with said scanning, and means for supplying said signal to said reproducing means whereby a picture of said scene is obtained.

6. In combination, means for imaging radio waves from a scene to be recorded, a radio wave pick-up device comprising a wave guide having an open end positioned to receive energy from said image and having the other end mounted on and terminating in a rotatable wave guide joint, means for scanning the said radio wave image by said pick-up device and converting the energy thu picked up into an electrical signal, an image reproducing means, means for operating said image reproducing means in synchronism with said scanning, and means for supplying said signal to said reproducing means whereby a picture of said scene is obtained.

HARLEY A. LAMS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Disclaimer 2,419,024.Harley A. lams, Princeton, N. J. RADIO VIEWING SYSTEM. Patent dated Apr. 15, 1947. Disclaimer filed June 30, 1950, by the assignee, Radio Corporation of America. Hereby enters this disclaimer to claim 4 of said patent.

[Ofiic'ial Gazette August 8, 1.950.]

Disclaimer 2,419,024.Harley A. Jams, Princeton, N. J. RADIO VIEWING SYSTEM. Patent dated Apr. 15, 1947. Disclaimer filed June 30, 1950, by the assignee, Radio Corporation of America. Hereby enters this disclaimer to claim 4 of said patent.

[Oflicial Gazette August 8, 1.950.] 

